Adding a bigger radiator without increasing the coolant flow rate (Bigger pump or turning the old pump faster) can reduce performance because of low coolant flow rate in the tubes.

Anything you can do to improve airflow through the radiator core will help. Anything that blocks or slows airflow, either before or after the radiator, will hurt.

Increasing the face area of the radiator will help.

Anything you can do to increase the coolant flow rate (The ideal coolant flow velocity through the radiator tubes in the range of 6 to 8 feet per second.) will improve heat transfer and cooling. Anything you do to restrict the coolant flow rate will hurt cooling.

A missing fan shroud can reduce the fan’s cooling effectiveness by as much as 50 percent (depending on the fan’s distance from the radiator)

Makes me wonder how well the Poison Spyder hood louvers might help at speed. I know the low pressure in front of the windshield is why I placed my cowl scoop facing back. I've seen how much air comes out the hood louvers by the way rain water reacts, I'm hoping opening up the flow of air from the front of the rad and out the hood will keep the air from having to exit under the jeep and increase flow...I hope, but unless you have a wind tunnel it's hard to know what air will do.

Just got busted by Chris. I`d rather not recall the number of days and weeks sweating my *** off when doing HWT (Hot Weather Testing) for one of Detroit`s big three.

So I am not going to do a soap box speech. Thing is that the testing encompasses real world testing often ballasted with weight far and beyond what the vehicle is design to haul/tow.

My 4.9 stroker runs at 195 to 210 be it freeway/traffic jam. Factory cooling with the exception of a CSR BRASS/COPPER radiator.

Hanging off the bumper blocking airflow is a winch, lights, couple of mounts and a PS/cooler.

Ditch the electric and do it right. No way in hell are you going to get the air flow those little blades of the electric fan and minimal shroud as shown in the picture.

Sorry but truth hurts and this electric fan is just another internet spawned myth that folks have sucked up to.

When I worked with Ron Davis and CBR radiators they wouldn't even sell me a radiator based on my needs. Their advice ? Go OEM

Not to say electric fans don`t have there place. They do when designed as a package with the entire cooling system taken as a whole.

No hurt feelings here John. I posted to get answers and solutions to my problem and if going back to my stock setup is the best answer then so be it. I just need to see if I can find my pulley and I know my fan blade is long gone. That is if my current setup is not the answer I'm looking for. I initially wanted more cooling on the trails because my fan clutches just couldn't keep up when crawling in July in the North Georgia Mountains.

Let's say I decide to go back to stock:

-Would my current radiator be optimal? (Autozone single aluminum core with plastic caps)
-If you can't source a Mopar fan clutch, where would you get one?

I can find a shroud and blade online and I would be tempted to get a thermostat from the dealer and get a new NAPA waterpump. I also need to see if I kept my pulley. I may not have.

That's why I have kept my cooling system all Mopar.
I see what they do to these vehicles as they leave town early in the morning.
I saw a Jeep (not sure what it was exactly, it was camo'd) it had a u-haul trailer with 3 water tanks strapped to it. WAY over weight. It also had half the grille blocked with a tarp.

That's why I also say they didn't leave the dealership overheating.
It irritates me when people say Jeeps have these "known" faults like the cooling system. When actually, for the first 15 years of life no one bothered to open the radiator cap.
Then they attempt to re-engineer the cooling system which left the factory as a balanced unit able to take on the hottest conditions on the planet.

This might work (barely) for a guy in Northern Minnesota where a hot day is 85.

Louie, good job on the shroud. My bla bla bla is not directed at you, I think your setup will work just fine.

I hope it works but I like to hear the best way to do things and folks experiences. We'll see how this goes.

Lou

I have a jeep...and it is modified...I win.

YJOTM July 2012YJOTM February 2014

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-Would my current radiator be optimal? (Autozone single aluminum core with plastic caps)Louie, without knowing the thermal efficiency of your AZ radiator it would be difficult to answer that question. Personally I would feel that it would not be as good as factory but how much less in open to speculation. You have heat transfer, construction, fin counts as just starters to compare.-

If you can't source a Mopar fan clutch, where would you get one? The clutch is an issue. However all is not lost. While we cannot be sure of the viscous fluid within the clutch or the vane design internally of the current off the shelf replacement parts we do have the ability to adjust the bi-metal spring that acts as the thermostat. Goggle is your friend with a number of links on how to do this very thing. Another good option would be to purchase a quality clutch from a company like Derale for instance.

I can find a shroud and blade online and I would be tempted to get a thermostat from the dealer and get a new NAPA waterpump. I also need to see if I kept my pulley. I may not have.

Many will disagree but the extra cost of the dealer supplied stat is money well spent. They are not all the same as most folks are lead to believe. In fact many of the upper level players in the off road world will even demand dealer supplied anti freeze. There is a lot of information out there that gets into depth beyond green vs. orange or HOAT vs. non HOAT etc.

A stroll through the TJ forum on cooling can be educational. Folks like Blaine Johnson (mrblaine) know a thing or two about cooling and you can take what they say to the bank. Here on the YJ forum Joe Dillard is a good source. Many of the cooling facts that Joe has learned have come from Blaine.

Sad that more folks don`t fully understand the operation of the bi-metal fan clutch spring. It really is our friend.

I hope it works but I like to hear the best way to do things and folks experiences. We'll see how this goes.

Plastic tanks are never optimal. On copper/zinc (brass) the tanks exchange (roughly) 1500 btu's per hour, aluminim 700 btu's per hour, and plastic, almost none. This is only the tanks.
Aluminum and plastic has been used since the 80's to save money and weight.

I would like to know where Chrysler/AMC sourced their fan clutches. The aftermarkets do not seem calibrated or aggressive.
Electric fans are only efficient when they are NOT running (snicker)
When they are running, they are HP robbers. The energy is being converted from mechanical to electric then back to mechanical again with losses at each conversion.
I was wheeling and crawling last weekend in 105 degree weather and my temp never moved. 195 all day.

Then a K-5 Blazer alternator froze up and burnt all the belts. I towed it several miles out of the desert near Creech AFB and 50 miles back to Vegas down the highway with my Jeep. I did 65 to 70 the whole way except for a big hill, I was down to 40 or 50. Never exceeded 210 although the fan was noisy most of the time and I burnt up 1/2 tank of fuel in 50 miles.

The behemoth...

I still think your fan setup will work fine. You just need to dispose of a few btu's of heat.

I may keep an eye out for stock YJ cooling parts and collect them over time. When I get a shroud, a fan, and a pulley I'll get a new Napa water pump, OEM thermostat and flush my engine. I don't see any crud in it but I also haven't flushed it in years. I've only drained the coolant and refilled. I even plan on getting Mopar coolant. As for the radiator, I can't justify one from Mopar for now. I'll try out the one I have and hope for the best and if the cooling is still piss poor I may ante up. I do believe a properly working OEM system should take care of the additional load of towing, A/C, and some air flow blockage in the front. Whether or not it will handle all three, I think it will but can't say for sure.

Until then, I'll keep what I have. I had $13 and time invested in my little project this past weekend and with as much money as I've spent on my jeep over the last 14 years I don't think investing in a good cooling system will be a bad investment.

Lou

I have a jeep...and it is modified...I win.

YJOTM July 2012YJOTM February 2014

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Louie, glad to see you took the time to search out Blaine. As you can see he is a strong advocate of OEM parts.

For the vast majority of folks whom don`t know whom Blaine is......Let`s just say you may be running parts he designed on your Jeep right now. Plus add in his workings on the Savvy/Currie EMC jeep and also his involvement with Ultra4 and KOH.

I can honestly say that if it was not for Blaine my YJ wouldn't be as capable as it is. That goes for handling, steering, cooling and braking.

I read through everyone's post for the most part and no one mentioned the heater core. You could have a clog there and the blower fan is helping to mitigate the issue.

This sounds like the exact same issue I had with my S-10 where we replaced the radiator, water pump, thermostat, and nothing helped the overheating. Same thing would help cool it when turning on the vent fan, finally flushed the heater core out and a ton of crud came out. It was instantly better but soon clogged again. We then replaced the heater core to correct the issue.

I would test this theory before buying a new radiator. You could probably bypass the heater core to diagnose temporarily.

The problem with that, is the heater core shouldn't be factored in as part of your cooling capacity. Otherwise, when you need the cooling the most, towing up a desert mountain in the triple digits, you will need to run your heater full blast. Your system should be able to run fine without the added radiator of the heater core.

My sons heater core was clogged with rust from a previous motor. That contributed to his over heating as it slowed the water circulation. Not to mention some of the heater core rust traveled back into the radiator. When you flush your system be sure to flush out the heater core as well. The water should flow both ways fairly easy without any pressure build up in the hoses.